I am struggling with them.
Donjons feel clunlky, specially in feudal. Sargents build them slowly and dont fire extra arrows although they cannot be interrupted by damage like villagers while doing so.
Donjons cost 200 stone. Their UT need both. A castle and some TCs to be noticeable. Thus, they need a lot of stone. If you go donjons, you cannot boom or build a castle.
Besides their infantry, all their land untis miss some important upgrade, although fortunatwly they have their defensive bonus to ignore bonus damage.
What are the ideal army comp for them in open maps?